Abstract

A clinical case of orthodontic treatment of an adult patient with maxillary prognathism is presented in the article. The patient refused orthognathic surgery. Extraction of individual teeth and distalization of lower posterior with fixed buccal appliances.

Introduction

Skeletal distal occlusion is one of the most common dentoalveolar abnormalities that influence the quality of life. In recent years, young patients understand more and more the necessity to correct the bite abnormalities and they are ready to go for orthodontic treatment [1]. However, diagnosis and treatment of the patients with distal occlusion are difficult for many practicing orthodontists. An important task in diagnosis and treatment approach is to determine main signs of the abnormality, their causes and relationship with dentoalveolar and/or skeletal forms of the abnormality. At that, determination of posterior (especially maxillary) teeth position in sagittal, horizontal and vertical planes aredifficult for doctors. The present work is devoted to examination of the approach to treat patients with dentoalveolar pathology.

In patients with distal occlusion and adapted TMD, bite abnormality doesn’t need to be treated and may be considered as individual normality (Slavicek R. “Masticatory Organ: Functions and Dysfunctions”, “Azbuka” 2008). However distal occlusion is often accompanied by horizontal and transversal disturbance of relationship of front teeth what affects the smile of the patient in the process of his complaints. It is often the cause to consult an orthodontist. In these case patient motivation and necessity of treatment coincide. Distal occlusion is a multifactorial abnormality with dentoalveolar and/ or skeletal component. One of the important steps in treatment planning is diagnosis of abnormalities causing distal occlusion and disturbance of relationship of front and posterior teeth. Difference between dentoalveolar, skeletal or mixed forms demands examination of the pictures of the patient’s face, study models, panoramic X-rays, head cephalometric, side and front (on indication) views.

Position and inclination of incisors and molars, upper incisors to the skull base, lower incisors to the plane of the lower jaw body, interincisal angle (angle ii).

Besides it is necessary to study facial signs of the full face front and profile:

symmetry of the face;

position of the lips relative to esthetic line;

Position of the chin relative to facial angle and nasal axis.

Treatment plan of adult patients with skeletal distal occlusion may include fixed appliances-bracket-arch systems, additional appliances without extraction of the teeth, with extraction of individual teeth and orthognathic surgery. Distalization of upper molars, which is usually the common way of treatment in children with Class II abnormality, is difficult in adult patients due to eruption of the 2nd and 3rd molars [3,4]. In recent years the use of microimplants for anchorage and corticotomy increased the efficacy of the replacement of the upper teeth. The most effective way of teeth correction is orthognathic surgery, which may have psychosomatic contraindications and patients’ unwilling to do a maxillofacial surgery.

Results

After analysis of jaw anthropometric models we determined 7 mm deficiency of space in the mandible. Thus extraction of two lower premolars would lead to expressed shortening of lower dental arch and reduction of space for tongue. As this patient has normal relations between lower and upper front teeth (Tonn formula), extraction of one of the lower incisors would prevent formation of good cusp-to-fissure occlusal contacts in posterior teeth. It was decided to distalize lower posterior teeth with extraction of lower third molars (Figure 7).

Post-op headcephalometric, side view, (Figure 8) reflects improvement of parameters (angle SNA= 84, 5°), mandibular retroinclination is less expressed (angle SN/ML=37, 0°), normal inclination 3L (3/ML=100,0°), considerable improvement of inclination of upper and lower incisors (angle 1u/SN=101,0°, 1l/ML=110°), interincisal angle-physiologic standard (ii=131, 8°). Type of profile and skeletal class II malocclusion correlation between them not necessary (Figure 9). Many malocclusions have disgnatizm, although it does not exclude the ideal visible occlusal contacts at the posterior teeth. Therefore, an important task in diagnosis and treatment approach is to determine main signs of the abnormality, their cause and relationship with dentoalveolar and/or skeletal forms of the malocclusion to detect hidden pathology. Being that Skeletal Class II malocclusion can be masked due to mesial displacement of both upper and lower teeth, mimicking Angle Class I. Post-op-cephalometric, side view, reflects improvement of parameters: mandibular retroinclination is less expressed, normal inclination of canines, considerable improvement of inclination of upper and lower incisors, interincisal angle -physiologic standard (ii=130, 1°- 131, 8°). And long-term results are stable.

Conclusion

Analyzing these cases report based on long-term results, we can conclude that the treatment of skeletal Class II malocclusion without orthognatic surgery indications for upper premolar extraction depends from severity of Maxillary Prognathizm and mesial inclination of posterior upper teeth. Lower molars distalization depends from mesial inclination of posterior low teeth. Regardless of the differences with the generally accepted standards for the facial profile and incisor’s inclinations, interincisal angle at the end of treatment corresponded to normal and, therefore, a good physiological load of these teeth.